/// <summary>
/// Add the checksum integer to header buffer.
/// </summary>
/// <param name = "value"></param>
/// <param name = "buffer">The header buffer to set the checksum for</param>
/// <param name = "offset">The offset into the buffer for the checksum</param>
/// <param name = "length">The number of header bytes to update.
/// It's formatted differently from the other fields: it has 6 digits, a
/// null, then a space -- rather than digits, a space, then a null.
/// The final space is already there, from checksumming
/// </param>
/// <returns>The modified buffer offset</returns>
static int GetCheckSumOctalBytes(long value, byte[] buffer, int offset, int length)
{
TarHeader.GetOctalBytes(value, buffer, offset, length - 1);
return(offset + length);
}